1. Field of Invention
Various embodiments of the present invention relate to an electronic device, and more particularly, to a semiconductor memory device and an operating method thereof.
2. Description of Related Art
Semiconductor memory devices can be largely classified into volatile memory devices and nonvolatile memory devices.
Nonvolatile memory devices have a relatively slow writing and reading speed but can retain the data stored even if the power is turned off. Therefore, nonvolatile memory devices may be used to store data that must be retained regardless of the status of the power supply. Examples of nonvolatile memory devices include a read only memory (ROM), a Mask ROM (MROM), a programmable ROM (PROM), an electrically programmable ROM (EPROM), an electrically erasable and programmable ROM (EEPROM), a flash memory, a phase-change RAM (PRAM), a magnetic RAM (MRAM), a resistive RAM (RRAM), and a ferroelectric RAM (FRAM).
Besides retaining their stored data when power is turned off, flash memory devices also have also the advantage of allowing data or programs stored therein to be readily erased. Flash memory devices are widely used as storage media for portable electronic devices, such as digital cameras, Personal Digital Assistants (PDAs) and MP3 players. Flash memory devices may be classified into NOR and NAND type flash memory devices.